1. Field of the Invention
This invention relates generally to a device for monitoring an infant for the onset of sudden infant death syndrome (SIDS), detecting the onset of SIDS and providing immediate treatment. Treatment could include instructions for administering cardiopulmonary resuscitation (CPR) as well as delivery of a defibrillation pulse from an automatic or semi-automatic external defibrillator (AED). The device may be a SIDS monitor as well as a SIDS trainer, or a SIDS monitor which has the ability to function as a trainer.
2. Description of the Prior Art
SIDS is a phenomenon which has been used to describe the sudden unexpected and unexplained death of an infant. Infant mortality is classified as SIDS when, despite a thorough investigation, no explanation can be found for the death of the infant. Currently, the incident of SIDS in the United States is approximately 1.6 per 1000 live births; upwards of 10,000 deaths per year in the United States alone. SIDS is the most common cause of death among children from one to six months of age.
Because SIDS is identified in situations where no explanation for the death can be found, the potential causes of SIDS has been largely speculative. Potential causes include cardiac disorders, respiratory abnormalities, gastrointestinal diseases, metabolic disorders, injury and child abuse.
Many devices have been developed that provide a way to monitor an infant for the onset of SIDS by detecting cessation of movement, cessation of respiration or detection of urination that may accompany agonal movement. Other devices have been developed to prevent SIDS from occuring, such as by providing an oxygenated mattress. The following summarizes a selection of previously patented approaches to SIDS detection and/or prevention.
U.S. Pat. No. 4,306,567 to Krasner describes a detector and monitoring device to be used to detect the onset of SIDS. The device of Krasner is an apnea monitor that is non-contacting. The device of Krasner detects the acoustical signal generated as a function of the breathing cycle to determine whether or not the infant is breathing.
U.S. Pat. No. 4,738,266 to Thatcher describes an apnea monitor. The device of Thatcher is in the form of a crib with a hood over the top. The hood collects the exhaled breath of in infant. Infrared energy is emitted into the hood and monitored such that, as long as CO.sub.2 is present in the hood (from exhaled breath), the device continues in monitoring mode. However, if the level of CO.sub.2 decreases there will be a corresponding change in the IR activity and an alarm will sound.
U.S. Pat. No. 4,851,816 by Macias et al. is directed to an apparatus for detecting the moment of urination for an infant. According to Macias, it is estimated that 85% of SIDS victims have some sort of agonal motor activity. Since urination would be expected to accompany agonal motor activity, by detecting the moment of urination, a parent would be alerted to the onset of SIDS and would attend to the infant. Additionally, a cardioverter is provided to stimulate conduction of tetanic contraction in an offending muscle by stimulating reflexive hyperdistension. One drawback of the device described by Macias is that it cannot detect the difference between urination as a result of agonal movement and urination generally. As a result, a parent might be watchful initially, but after a few days or weeks, would likely either discontinue using the device or would not respond immediately thereby eliminating the potential likelihood of discovering SIDS within the first few minutes.
U.S. Pat. No. 5,277,194 by Hosterman et al. is directed to a breathing monitor and stimulator. Hosterman provides an apparatus that is worn around the chest of the infant and monitors the breathing pattern. A bladder is provided in the device that can be cyclically operated to induce breathing when either a change in breathing rate is detected or cessation of breathing. An alarm may also sound when the device detects a change in breathing pattern, thus alerting a primary caregiver that a problem exists.
U.S. Pat. Nos. 5,317,767; 5,483,711 and 5,787,534 are a series of patents to Hargest et al. directed to a safety pad for use in a crib which prevents SIDS by ensuring an oxygenated breathing space beneath the infant. As noted in Hargest et al., the weight of an infant's head relative to the rest of the body is quite high. Further, the next muscles of an infant are not well developed. Thus, if an infant is placed in the prone position for a nap (i.e., on their stomach) and they attempt to turn their head from one side to the other they could become stuck with their face pressed into the mattress due to lack of strength of their neck muscles. This would result in suffocation. Thus, the apparatus of Hargest et al. would prevent such suffocation by providing an oxygen saturated mattress.
U.S. Pat. No. 5,505,199 to Kim is a monitor which determines oxygen saturation and movement. When a change in oxygen saturation is detected along with lack of movement, the device brings a video image of the infant into the parent's room, thus enabling the parents to see the condition of the child.
U.S. Pat. No. 5,615,688 to O'Dwyer is directed to an apnea detection device. A strap is provided for the wearer's chest. The strap provides a detection mechanism in a housing for monitoring the respiration of an infant. A transmitter is also provided which transmits a signal to a receiver in the event that an anomoly in breathing is detected. Upon receipt of the signal from the transmitter the receiver emits an alarm to warn of the breathing anomoly.
U.S. Pat. No. 5,360,008 to Campbell Jr. is directed to a respiratory and cardiac monitor. Campbell Jr. monitors the electromagnetic permeability of the trunk, which changes during the respiratory cycle, to detect the respiratory cycle and cardiac cycle. A receiver/transducer is worn on a belt by the patient. The receiver/transducer communicates with a transmitter/transducer which is mounted on a suitable housing and disposed within close proximity to the receiver/transducer. An electronic signal which is modulated in its amplitude by the varying permeability of the patient's body (occurring during the respiration process) is sent by the receiver/transducer to the transmitter/transducer. The received signal is amplified and filtered to obtain a signal corresponding to the patient's pulse and the patient's respiration.
U.S. Pat. Nos. 5,515,865 and 5,648,460 to Scanlon is directed to a fluid-filled sensing pad for supporting an infant. The pad uses a transducer to detect movement or acoustic activity. When no movement or acoustic activity is detected a stimulator is activated to move the infant.
U.S. Pat. No. 5,774,055 by Pomerantz is directed to an infant monitoring device comprising a sensor connected to an alarm. The sensor can alert a parent if the infant assumes a predetermined position. Alternatively, the sensor can alert a parent if the infant is in the same position for a period of time exceeding an amount provided for by the sensor.
U.S. Pat. No. 5,825,293 to Ahmed et al. is directed to a method and apparatus for monitoring breathing magnetically. A magnet is placed so that it moves in common with either the abdominal wall or the chest wall. A receiver is placed, for example, at the edge of the crib. As the magnet moves up and down with the infant's respiration, the receiver detects the resulting change in distance from the receiver. If the infant stops breathing, no change in distance is detected and an alarm is sounded.
One disadvantage of the prior art solutions is that the systems are easily activated by conditions other than the onset of SIDS. These false alarms could condition the caretaker to be less diligent in responding to the alarm and might result in an actual SIDS episode escaping detection.
As is evident by the prior art solutions, it has been hypothecated that SIDS is the result of apnea or suffocation. Recently, however, a study by Schwartz et al. indicated that, in many cases, SIDS victims have a history of long QT syndrome. Schwartz et al. "Prolongation of the QT Interval and the Sudden Infant Death Syndrome" NEJM 338(24):1709-1714 (1998). Schartz et al. recorded ECGs for 34,442 newborn babies over a period of 18 years. The discovered that the infants that died from SIDS typically had a longer corrected QT interval that the survivors. Long QT is known to be a marker of cardiac electrical instability which indicates a predisposition to fatal cardiac arrhythmias. As a result, even if SIDS were detected by using one of the prior art solutions, a caretaker would stand by helpless to provide assistance and would have to wait until emergency medical personnel arrived.
As will be appreciated by those skilled in the art, for those SIDS occurrences that result from a cardiac arrhythmia, blood may no longer be pumping effectively. If blood is no longer pumping effectively, it is imperative that effective resuscitative efforts begin as soon after the onset of the condition as possible since brain damage can occur after the brain is deprived of oxygen for four to six minutes. Resuscitative efforts include CPR and defibrillation if a shockable cardiac arrhythmia exists.
What is needed is a device that monitors the respiration and/or cardiac activity of an infant identified with long QT syndrome who may be at high risk for SIDS and then provides an effective mechanism for initiating treatment until an emergency medical technician (EMT) arrives.